RFR: 8225429: Regression in disassembly quality

[Ioi Lam]

Hi Andrew, thanks for fixing this. I tried it and it worked for me :-)

I also tried "java -XX:+PrintInterpreter -version" and the comments from 
the C++ source code has come back to life.

- Ioi

On 6/6/19 8:19 AM, Andrew Haley wrote:
> In a debug build, if you printed a disassembled method, you used to
> get a lot of information about a method. Now, you just get raw
> disassembly. This patch restores the status quo ante,
>
> http://cr.openjdk.java.net/~aph/8225429-1/
>
> There are other bugs in the new disassembly output: in particular
> options processing seems to be very broken. However, this patch is
> enough to get things going again, so at least we can get some work
> done.
>
> Before:
>
>    # {method} {0x00007f2f64833660} 'decodeModuleName' '(ILjava/lang/String;)Ljava/lang/String;' in 'jdk/internal/module/ModuleInfo$ConstantPool'
>    # this: rsi:rsi = 'jdk/internal/module/ModuleInfo$ConstantPool'
>    # parm0: rdx = int
>    # parm1: rcx:rcx = 'java/lang/String'
>    # [sp+0x40] (sp of caller)
>   ;; N542: # B1 <- BLOCK HEAD IS JUNK Freq: 1
>
>    0x00007f2fb1168440: mov r10d,DWORD PTR [rsi+0x8]
>    0x00007f2fb1168444: movabs r12,0x800000000
>    0x00007f2fb116844e: add r10,r12
>    0x00007f2fb1168451: xor r12,r12
>    0x00007f2fb1168454: cmp rax,r10
>    0x00007f2fb1168457: jne 0x00007f2fb104d6a0 ; {runtime_call ic_miss_stub}
>    0x00007f2fb116845d: nop
>    0x00007f2fb116845e: nop
>    0x00007f2fb116845f: nop
> [Verified Entry Point]
>   ;; B1: # B54 B2 <- BLOCK HEAD IS JUNK Freq: 1
>
>    0x00007f2fb1168460: mov DWORD PTR [rsp-0x16000],eax
>    0x00007f2fb1168467: push rbp
>    0x00007f2fb1168468: sub rsp,0x30 ;*synchronization entry
>                                                  ; - jdk.internal.module.ModuleInfo$ConstantPool::decodeModuleName at -1 (line 877)
>
>    0x00007f2fb116846c: mov r10,rsi
>    0x00007f2fb116846f: mov r9,rcx
>    0x00007f2fb1168472: mov edi,DWORD PTR [rcx+0xc] ;*getfield value {reexecute=0 rethrow=0 return_oop=0}
>                                                  ; - java.lang.String::length at 1 (line 658)
>                                                  ; - jdk.internal.module.ModuleInfo$ConstantPool::decodeModuleName at 1 (line 877)
>                                                  ; implicit exception: dispatches to 0x00007f2fb116872a
>   ;; B2: # B55 B3 <- B1 Freq: 0.999999
>
> Now you only get this, even in a debug build:
>
>    0x00007ff1c5176c20: mov r10d,DWORD PTR [rsi+0x8]
>    0x00007ff1c5176c24: movabs r12,0x800000000
>    0x00007ff1c5176c2e: add r10,r12
>    0x00007ff1c5176c31: xor r12,r12
>    0x00007ff1c5176c34: cmp rax,r10
>    0x00007ff1c5176c37: jne 0x00007ff1c5113da0
>    0x00007ff1c5176c3d: nop
>    0x00007ff1c5176c3e: nop
>    0x00007ff1c5176c3f: nop
>    0x00007ff1c5176c40: mov DWORD PTR [rsp-0x16000],eax
>    0x00007ff1c5176c47: push rbp
>    0x00007ff1c5176c48: sub rsp,0x30
>    0x00007ff1c5176c4c: mov r11,rsi
>    0x00007ff1c5176c4f: mov r9,rcx
>    0x00007ff1c5176c52: mov r10d,DWORD PTR [rcx+0xc]
>
> There are no comments at all, just raw disassembly.
>
> This patch restores the status quo ante:
>
>    # {method} {0x00007f9f53c2e3c0} 'decodeModuleName' '(ILjava/lang/String;)Ljava/lang/String;' in 'jdk/internal/module/ModuleInfo$ConstantPool'
>    # this:     rsi:rsi   = 'jdk/internal/module/ModuleInfo$ConstantPool'
>    # parm0:    rdx       = int
>    # parm1:    rcx:rcx   = 'java/lang/String'
>    #           [sp+0x40]  (sp of caller)
>   ;; N551: #     out( B1 ) <- BLOCK HEAD IS JUNK  Freq: 1
>    0x00007f9fb4d64620:   mov    r10d,DWORD PTR [rsi+0x8]
>    0x00007f9fb4d64624:   movabs r12,0x800000000
>    0x00007f9fb4d6462e:   add    r10,r12
>    0x00007f9fb4d64631:   xor    r12,r12
>    0x00007f9fb4d64634:   cmp    rax,r10
>    0x00007f9fb4d64637:   jne    0x00007f9fb4cfeda0           ;   {runtime_call ic_miss_stub}
>    0x00007f9fb4d6463d:   nop
>    0x00007f9fb4d6463e:   nop
>    0x00007f9fb4d6463f:   nop
> [Verified Entry Point]
>   ;; B1: #       out( B55 B2 ) <- BLOCK HEAD IS JUNK  Freq: 1
>    0x00007f9fb4d64640:   mov    DWORD PTR [rsp-0x16000],eax
>    0x00007f9fb4d64647:   push   rbp
>    0x00007f9fb4d64648:   sub    rsp,0x30                     ;*synchronization entry
>                                                              ; - jdk.internal.module.ModuleInfo$ConstantPool::decodeModuleName at -1 (line 876)
>    0x00007f9fb4d6464c:   mov    r11,rsi
>    0x00007f9fb4d6464f:   mov    r9,rcx
>    0x00007f9fb4d64652:   mov    r10d,DWORD PTR [rcx+0xc]     ;*getfield value {reexecute=0 rethrow=0 return_oop=0}
>                                                              ; - java.lang.String::length at 1 (line 673)
>                                                              ; - jdk.internal.module.ModuleInfo$ConstantPool::decodeModuleName at 1 (line 876)
>                                                              ; implicit exception: dispatches to 0x00007f9fb4d648fe
>   ;; B2: #       out( B56 B3 ) <- in( B1 )  Freq: 0.999999
>